Maintenance and Replacement Recommendations: The service life of coagulation filter cartridges (E9, E7, E5, E3) is generally 2000 to 4000 hours (or must be replaced when the differential pressure gauge enters the red zone); activated carbon filter cartridges (E1) cannot be reflected by differential pressure after full adsorption, so it is generally recommended to replace them at around 1000 hours to prevent excessive odor.